AWS Lambda获取s3对象数据模板不工作

Question

我正在努力理解Amazon Lambda。这只是对s3模板进行了轻微修改，以查看上传文件的内容类型。

我收到的事件日志和params日志都显示在cloudwatch中，但就像s3.getObject（）永远不会被执行一样，因为数据日志的错误日志都不会显示在日志中，我得到的只是一个超时后超时的任务。

var aws = require('aws-sdk');
var s3 = new aws.S3({apiVersion: 'latest'});
exports.handler = function(event, context) {
    console.log('Received event:', JSON.stringify(event, null, 2));
    // Get the object from the event and show its content type
    var bucket = event.Records[0].s3.bucket.name;
    var key = decodeURIComponent(event.Records[0].s3.object.key.replace(/+/g, ' '));
    var params = {
        Bucket: bucket,
        Key: key
    };
    console.log(params);
    s3.getObject(params, function(err, data) {
        if (err) console.log(err, err.stack); // an error occurred
        else     console.log(data);           // successful response
/*
        if (err) {
            var message = "Error getting object " + key + " from bucket " + bucket +
                ". Make sure they exist and your bucket is in the same region as this function.";
            console.log(message);
            context.fail(message);
        } else {
            console.log('CONTENT TYPE:', data.ContentType);
            context.succeed(data.ContentType);
        }
*/
    });
};

以下是当前IM角色，我需要做一些更改吗？

{
    "Version": "2012-10-17",
    "Statement": [{
        "Effect": "Allow",
        "Action": [
        "logs:CreateLogGroup",
        "logs:CreateLogStream",
        "logs:PutLogEvents"],
        "Resource": "arn:aws:logs:*:*:*"
    },
    {
        "Effect": "Allow",
        "Action": [
        "ec2:CreateNetworkInterface",
        "ec2:DescribeNetworkInterfaces",
        "ec2:DetachNetworkInterface",
        "ec2:DeleteNetworkInterface"],
        "Resource": "*"
    },
    {
        "Effect": "Allow",
        "Action": [
        "s3:ListAllMyBuckets",
        "s3:ListBucket",
        "s3:GetBucketLocation",
        "s3:GetObject",
        "s3:PutObject"],
        "Resource": "arn:aws:s3:::*"
    },
    {
        "Action": "lambda:*",
        "Effect": "Allow",
        "Resource": "arn:aws:lambda:*"
    }]
}

Answer 1

我以前遇到过这个问题。这种情况发生在验证、构建和签名回调执行之后，但在发送回调发生之前。本质上，其中一个套接字进入僵尸模式。我已经向AWS报告了这一点，但他们还没有做出修复。要"修复"，请在实例化s3客户端时设置套接字超时。套接字将超时，操作将自动重试。

var s3 = new AWS.S3({httpOptions: { timeout: 2000 }});

默认情况下，超时时间为两分钟，这就是为什么在超时时间明显更短的Lambda中发生这种情况会有问题。

Answer 2

在ListBucket之前，您需要ListAllBuckets。我建议您限制您的lambda访问权限。

{
       "Statement":[
      {
         "Effect":"Allow",
         "Action":[
            "s3:ListAllMyBuckets"
         ],
         "Resource":"arn:aws:s3:::*"
      },
      {
         "Effect":"Allow",
         "Action":[
            "s3:ListBucket",
            "s3:GetBucketLocation"
         ],
         "Resource":"arn:aws:s3:::yourBucket"
      },
      {
         "Effect":"Allow",
         "Action":[
            "s3:GetObject"
         ],
         "Resource":"arn:aws:s3:::yourBucket/*"
      }
       ]
    }

Answer 3

您必须在lambda的末尾包含一个显式回调，否则它将在s3回调函数被命中之前自动停止运行。

例如：

module.exports.getS3Object = async (event, context, callback) => {
  const AWS = require('aws-sdk');
  const S3 = new AWS.S3();
  S3.getObject({ Bucket: "exampleBucket", Key: "exampleKey" })
    .promise()
    .then(data => console.log("finished"))
    .catch(err => console.log("there was an error" + err))
  callback(null, {statusCode: "200", body:"yay"}); //MUST INCLUDE
}